Detergent additives in motor gasoline have come a long way since they were first developed and introduced commercially in 1954 by the Standard Oil Company of California (now Chevron). Limits on vehicle emissions to the atmosphere and mandated fleet fuel economy have made effective deposit control additives essential in modern automotive gasolines. This paper will describe how it all started.The problem that inspired this development was called carburetor gumming. Taxicab fleets and other cars engaged in stop and go service developed symptoms of rich, rough idling that required frequent idle mixture adjustment and eventually cleaning of the carburetor. Engine blowby ingested at idle from the oil fill cap and draft tube was determined to be a major source of the problem. A quick test using a laboratory engine equipped with a glass carburetor throttle body and the blowby piped into the air intake simulated thousands of miles driving in two hours. It was the key for screening fuel additives. After false starts using oil and aromatic hydrocarbons as gasoline additives, an organic detergent was found that resulted in clean throttle bodies when used at a concentration of only 30 parts per million (ppm) by weight. Field tests confirmed the effectiveness not only in preventing the buildup of deposits, but in cleaning up previously existing deposits. In less than a year gasoline containing the additive was brought to market.Our SAE paper, “The Cause and Correction of Carburetor Gumming,” presented in the fall of 1954, introduced this development. Now, with the wraps of competitive secrecy removed and a third of a century of hindsight, considerably more can be said.